Soft Skin System and planned Jiggle Physics (Patreon)

Everyone's seen jiggle physics by now, and game engines offer really good support for them, which means they're abundant in most lewdy projects. 

If anyone's familiar with rigging, you'll probably know how most games' jiggle physics are done - with bones in the breast / ass which the skin is weight painted to, and a jiggle / spring solver is applied to the bone to make it lag and bounce behind the rigid bones in the skeleton as if it's attached via a spring.

Naughty Sandbox will use this system everywhere in the body, wherever natural bounces will occur. Not sure why they're mostly constrained to the breasts in other games, when calf muscles, thighs, bellies etc also bounce. 

I'd also like to do something I haven't seen many (any?) games do - barely even CGI animation does this which is a shame - skin depressions and surface ripples. While bone jiggle physics deal with large areas of the body bouncing and jiggling, there's not much of a solution for precise surface squishiness, such as poking your finger into a girl's soft belly. 

I was determined to solve this issue and so built a shader system that allows things in the world to lovingly inject their coordinates into the girl's material. The system in a general sense can be used for converting a point in space to a pixel on a texture so, broadly, any time we want to convert doing something physically to doing something in a material, we can.

Some examples - dripping oil onto a girls' skin can make her oily and wet by editing the parameters of specularity and roughness in her material where the drop landed on her. Spanking her with a paddle can make her skin red exactly where the paddle hit her by editing her base color parameters. And touching or squeezing her can make her skin depress by modifying her material's vertex offsets, to literally push those parts of the mesh inward where you touched her. 

The clip above is an example of this, using Valve Knuckles controllers to poke, with the fingers adding dimples into her skin. Depending on the depth of the poke, the deeper the depression. The clip is only a work in progress so far and I'll hopefully have a realistic looking example to show off soon!

Additionally, during slaps, spanks, collisions etc that involve soft flesh, the fat and muscle will ripple like a wave across the body until the energy has dissipated or until the wave reaches much leaner flesh. I want to simulate this too, with animated ripple maps that will play over the surface of her body. 

This system and the touching system can be modified to be more or less intense on certain areas of the body, so we can represent hard areas such as the knees that won't be able to be depressed much and won't jiggle and ripple when hit, and soft areas like the ass and belly, which will.

Hopefully this wasn't too technical or whatever, or maybe it wasn't technical enough if you're a nerd.